//! Provides [`Key`] and functions to encode & decode expiring claims.

use time::OffsetDateTime;

pub use crate::signed::Key;

/// Join a string and an expiry date together into a string.
pub fn encode_expiring_claim(claim: &str, expiry_date: OffsetDateTime) -> String {
    format!("{}:{}", claim, expiry_date.unix_timestamp())
}

/// Extract the string, failing if the expiry date is in the past.
pub fn decode_expiring_claim(value: String) -> Result<String,&'static str> {
    let mut parts = value.rsplitn(2, ':');
    let expiry_date = parts.next().expect("first .rsplitn().next() is expected to return Some");
    let claim = parts.next().ok_or("expected colon")?;
    let expiry_date: i64 = expiry_date.parse().map_err(|_| "failed to parse timestamp")?;

    if expiry_date > OffsetDateTime::now_utc().unix_timestamp() {
        Ok(claim.to_string())
    } else {
        Err("token is expired")
    }
}

#[cfg(test)]
mod tests {
    use time::{OffsetDateTime, Duration};

    #[test]
    fn test_expiring_claim() {
        for claim in vec!["test", "", "foo:bar"] {
            let encoded_claim = super::encode_expiring_claim(claim, OffsetDateTime::now_utc() + Duration::minutes(1));
            assert_eq!(super::decode_expiring_claim(encoded_claim).unwrap(), claim);

            let encoded_claim = super::encode_expiring_claim(claim, OffsetDateTime::now_utc() - Duration::minutes(1));
            assert!(super::decode_expiring_claim(encoded_claim).is_err());
        }
        assert!(super::decode_expiring_claim("test".into()).is_err());
    }
}